This invention relates to a process for treating gelatinous sludge agglomerations resulting from the clarification of raw water and more particularly to such a process which converts the gelatinous sludge into a filterable sludge whereby the solids of the filterable sludge may be readily separated from the liquids.
In the process of clarifying raw water from natural sources, such as lakes, rivers, wells and the like, to yeild potable water, it is the usual practice to add to the raw water coagulants, such as alum with or without an alkali, such as lime and/or a synthetic coagulant, such as poly acrylamides. As is well known in the art to which our invention relates, these additives provide nuclei which attract the fine suspended solids of coloidial size or larger so as to form macroscopic agglomerations, which, with quiescence, tend to settle from the water. In the operation of water filtration plants to produce potable water, the agglomerations accumulate in settling basins or are trapped in and on the filter media employed for water clarification. The agglomerates thus accumulated in the settling basin contain aluminum hydroxide sludge which is quite gelatinous whereby it does not lend itself to filtration or water extraction by conventional means.
Heretofore, it has been usual practice to dispose of such gelatinous sludges accumulated in settling basins by flushing the same into surface streams or by discharging the gelatinous sludge to drying beds. Due to the pollution of surface streams, it is very desirable to remove these solids from settling basins by means other than flushing such solids to streams. While some water filtration plants have the large areas required for drying such gelatinous waste, many plants do not have such large areas for drying this waste.